1. Field of the Invention
The present invention relates to a liquid crystal display device, and more particularly, to a method of fabricating a liquid crystal display device.
2. Discussion of the Related Art
Until recently, display devices have typically used cathode-ray tubes (CRTs). Presently, many efforts and studies are being made to develop various types of flat panel displays, such as liquid crystal display (LCD) devices, plasma display panels (PDPs), field emission displays, and electro-luminescence displays (ELDs), as a substitute for CRTs. Of these flat panel displays, LCD devices have many advantages, such as high resolution, light weight, thin profile, compact size, and low voltage power supply requirements.
In general, an LCD device includes two substrates that are spaced apart and face each other with a liquid crystal material interposed between the two substrates. The two substrates include electrodes that face each other such that a voltage applied between the electrodes induces an electric field across the liquid crystal material. Alignment of the liquid crystal molecules in the liquid crystal material changes in accordance with the intensity of the induced electric field into the direction of the induced electric field, thereby changing the light transmissivity of the LCD device. Thus, the LCD device displays images by varying the intensity of the induced electric field.
The LCD device is categorized into a transmissive type, a reflective type, and a transflective type. The transmissive type LCD device uses a backlight and thus can display images brightly in dark surroundings. However, the transmissive type LCD device consumes much power. The reflective type LCD device uses an external light such as sunlight instead of the backlight and thus can reduce power consumption. However, the reflective type LCD device cannot be used in dark surroundings or where the external light does not exist.
The transflective LCD device selectively operates in a transmissive mode or a reflective mode according to surroundings. Accordingly, the transflective LCI) device has advantage that each of the transmissive and reflective LCD devices has.
As the transflective LCD device, an IPS (in-plane switching) mode transflective type LCD device is used in order to improve viewing angles.
FIG. 1 is a cross-sectional view illustrating a pixel region of an array substrate for an IPS mode transflective LCD type device according to the related art, FIG. 2 is a picture illustrating disconnection defect of a common electrode of the LCD device according to the related art, and FIG. 3 is a cross-sectional view illustrating a process of forming the common electrode of the LCD device according to the related art.
Referring to FIG. 1, a pixel region P includes a reflective region RA and a transmissive region TA.
Although not shown in the drawings, gate and data lines crossing each other are formed on a substrate 2 and define the pixel region P. A common line in parallel with and spaced apart from the gate line is formed on the substrate 2. A thin film transistor is formed in the pixel region P and connected to the gate and data lines.
A reflective plate 50 is formed in the reflective region RA to reflect an external light. The reflective plate 50 is not formed in the transmissive region TA.
A pixel electrode 70 is formed on the reflective plate 50. The pixel electrode 70 is in the pixel region P.
A common electrode 80 is formed on the pixel electrode 70. The common electrode has a plurality of openings op1 and op2 that each have a bar shape. The openings op1 and op2 include first and second openings op1 and op2 that are located in the transmissive and reflective regions TA and RA, respectively. The first and second openings op1 and op2 are different in length direction.
The array substrate of the related art is fabricated through 9 mask processes. The mask process may include a process of depositing a material to be patterned, a process of depositing a photoresist, a light exposure process using a photo mask, a process of developing the light-exposed photoresist, a process of etching the material layer using the photoresist, a process of stripping the photoresist, and the like.
During the mask processes, some defects occur in the array substrate. Particularly, referring to FIG. 2, when forming the common electrode 80 after forming the reflective plate (50 of FIG. 1), frequently occurs a defect that finger portions of the common electrode 80 between the neighboring openings are disconnected.
Referring to FIG. 3, the finger portions of the common electrode (80 of FIG. 1) between the neighboring second openings opt in the reflective region RA are designed to have a width of about 10 μm to about 20 μm. In a light exposure process, light passing through a transmissive portion TA of a photo mask 95 may be reflected by the reflective plate 50 and then incident on a portion of a photoresist layer 91 that corresponds to a blocking portion BA of the photo mask 95 but the light should not be incident on.
After the light exposure process, the photoresist layer 91 is developed to form a photoresist pattern, and in the developing process, the photoresist layer 91 exposed to light is removed. Then, an etching is performed for a layer 79 to form the common electrode 80 using the photoresist pattern. Through the etching process, the common electrode 80 is formed.
However, as described above, the portion of the photoresist layer 91 below the blocking portion BA and in the reflective region RA is unintentionally exposed to light due to the reflection by the reflective plate 50. Accordingly, the portion of the photoresist layer 91 below the blocking portion BA is unintentionally removed in the developing process, and thus a portion of the layer 79, that becomes the finger portion of the common electrode 80, below the unintentionally removed portion of the photoresist layer is removed in the etching process. Therefore, the disconnection of the finger portion is caused.